Eaiiiway-trafe ic-contktolling apparatus



Sheets-Sheet l Apr. 17; 1923.

F. H. NICHOLSON RAILWAY TRAFFIC CONTROLLING APPARATUS Filed sept'. 12 1918 WITNESSES Apr'. 17, 1923. 1,452,214

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Patented Aprn 17, 1923.

UNITED STATES FRANK H. NICHOLSON, OF WILKINSBURG,

vSWITCH @c SIGNAL COMPANY, 0F. SWSSK 0F PENNSYLVANIA.

RAILWAY-TRAFFIC-CONTROLLING .PPltATU Application llled. September 1.2,

T 0 all whom it may concern;

Be it known that I, FRA-NK H; NICHOL- sox, a citizen oi? the United t'ltatca' residing at lllilkinsburg, in the county olf Allegheny and State of Pennsylvania, have invented certain new and useful Improve ments in Railway-Traliic-Controlling Apparatus, of which the following' is a specilication.

My invention relates to railway tratc controlling apparatus, and particularly to apparatus of the type in which an automatic brake application is caused if a car or train exceeds a certain speed limit under certain trafiic conditions, or violates other restrictions which may be imposed due to fixed conditions or to traic conditionsin advance of the car or train.

Various schemes have been proposed in the past whereby a train isckpermitted to pass a caution signal and proceed to the stop signal without an automatic brake applcation, provided the tra-in is so controlled by its operator that its speed never exceeds a predetermined maximum speed limit, which limit is determined by the automatic device carried by the train or car. The speed limit thus determined by the automatic device on the car or train is made to decrease gradually with the progress of the train through the block, so that the speed limit at any point within the block will be the same as the speed which would result from avbrake application of known intensity initiated at the entrance to the block. In other words, the speed limit thus obtained may be represented upon a speed-distance diagram by a curve, which curve may be made to coincide with a braking curve representing the known braking of the given train in the I.fri-ven block It is obvious that the braking distance and the braking curve for a given train depend upon the profile and alignment of the track over which the train is running; tor ers ample, if the grade is descending, the'braking distance will be greater than it the grade is ascending or it the track is'level.

In a fixed signal system where theblock lengths 'are determined by the braking curves or the braking ldistances Ytor a given train at a `afivenspeed,` and the braking distances vvary`,f freatly in length, there will be a large number et different braking curves, and a correspondingly large number of difjierent block lengths.

It the block length equal to the respective braking distance f 'i 'factor "i is obvious that the `loc.A `ion of the caution signal lirios the high speed end of the brakingcurve, and accordingly the operators oi" trains or cars running through such blocks are instructed and are accustomed to start the braking of the train at the location o the caution signal.

la?, to a railroad eoiuipped with liXed signals. above described, it is proposed to l" an automatic train control system proappr., ducing speed limit curves coinciding with the braking curves, it is apparent that the automatic device carried by`the train must .be capable oil producinnT a different speed limit curve for cach block length, or at least for cach group of nearly equal block lengths, and furthermore, it must be capable of selecting and produeine'` at the entrance of any blockA the particular speed limit curve which coincides with the braking curve for the given train in that particular block. These requirements have `resulted in certain complications and certain difliculties which it is proposed. to avoid by means of the present invention.

@lince the block length is equal to the braking distance plus a factor of safety, it is armaron that the speed limitrurve determi ed b v tbc automatic device discussed is not the braking curve representing the shortest stopping distance with the given trair at the maximum speed. The speed limit curve really represents a normal stop ci' tle t `r. when its speed is reduced, immediately utter passing the caution signal, bv a ln'ake application ci a degree just suliicieut (no more or no less) to bring it to rest at the stop signal,

Pinch accurate handling ot the train requires a deurce ot ,Y ll not usually found .in train operators or it requires a iorm ot air bril bv which the luukiug` effort can be incre sed or lessened at will and by the exact desiree required to keep the train close to but just below the sgiv ,A limit curve traced by the automati device carried by the train or car. The feature in the .air brake system by which tbc braking effort following a brake application is lessened in 4degree or graduated oil at will, is known as the Graduated release feature, and since this feature is not provided in the air brake systems of many trains or cars, it is apparent that it is'not practicable to control such trains or cars in the manner presupposed in the above -discussed automatic control system.

I have found, however, that the required safety-and accuracy may be obtained if the operators ot such trains or cars control them between the caution signal and stop signal by two itull service brake applications, separated by a period in which the brakes are released and the train is allowed to dritt. By this method, as soon as the cautionsignal is passed, the speed of the train is reduced along` a braking curve shorter than that whichv would be tracedby the automatic device discussed above, and the speed is thereby quickly brought below a certain intermediate or so-called controlled speed. The brakes may then be released, and the train allowed to drift to a point of second application, which obviously is the point at which a second tull service brake application will bring the train to rest at the stop signal.

F To control a train in this manner the operator will., as the train passes the caution signal, make a itull service brake application, and will then place his brake valve handle at the lap position and retain the application until the train speed has been` brought to the intermediate or controlled limit. ,He will then release the brakes and allow the train to dritt to the point of secondiapplication where a second i'ull service application will be made, which application will be held until the train has been brought to rest, or its speed brought below a predetermined low limit.

Inv actual practice the block lengths on most railroads do not correspond exactly with maximum braking distance plus the fixed factor of safety. ln such cases, the drilting-y distance between the two brake applications' will vary in ditl'erent blocks, the variation depending upon the extent to which the actual block lengths depart from the lengths determined by braking distance plus vfactor oit safety.

It will be noted that by the use oithis two-application stop the speed of' the train never exceeds the speed limit curve which would be set by the automatic device discussed above, and iiu it can be assured that the required or predetermined brake application will be made at the caution signal and at the second application point` and 'that each application will be held until the predetermined lower speed is reached, it is obvious that automatic means tor determinine' the theoretical speed limit curve is not required. and the complications and dilliculties involved in its operation are avoided.

One feature of my invention. then, is the provision oiz means for preventing1 an automatic application of the brakes it the operator controls the train by the two-application stop method which I have explained, that is, it he manually effects the braking inherently required to keep the train below the safe speed limit at every point in the block in the rear ot a stop signal.`

Another feature of my invention is the provision of means whereby the operator oi the car or train can suppress or prevent the operation ot the automatic device `for applyinp,V the brakes, by the act of applying the brakes in the usual manner; that is, by causing a brake pipe or equalizing reservoir reduction of a predetermined amount known to be sutlicicnt to bring the train to a stop or to a predetermined lower speed lat a point determined by the track or traflic conditions in advance.

Still another feature of my invention is the provision of means for penalizing the operator of the car` or train when the operator tails to observe or obey the roadside signal, by causing` the carf or train to come to a full stop whenever the automatic application of the brakes has occurred.

lf will describe one term and arrangement oiz apparatus embodying' my inyention, and will then point out the novel features thereof in claims.

ln the accompanying` drawings, Fig. l is a view, partly `diapufarnmatic, showing' one form and arrangement of vehicle carried apparatus embodying,` my invention. F 2 is a diagrammatic view showing-` one form of track'way apparatus which may bey employed in connection with the apparatus shown in Fig. l.

Similar reference characters refer to similer parts in each ofthe views.

Referring iirst to lii'g. l, it is understood that all ot the apparatus shown herein, except a contact rail A, is carried by a railway vehicle.` such as a car or locomotive, and that such vehicle is provided with av braking sys tem of the usual ,tluid pressure type. AThe only part oi this ln'akinn system whichv shown in the drawing, however, is the operating: handle oit` the engineers brake valve. 'this part being;P designa-ted Brake valve handle." ,-"iqttachcd to this handle is a cam 2 which controls a valve 4- in a casing- 3, this vulve beine' biased to the closed position by a spring' Si. rllhe cam is so designed that veli-,fe 4- is open when the valve handle is in llunnincg Release and Lap positions, but closed when the handle is in Service or l l/ilhen the valve 4i Emergency position. .is open. it opens a pipe 6 to atmosphere through a port 7.

The reference character V designates a valve device comprising a body havingf a larve cylinder at one end and a smaller cy at the other end. The large cylinder is connected with the equalizing reservoir ofthe inra-king,` system through a pipe 12, and the small cylinder 9 is connected with the feed valve of the braking system through a pipe 18. The large cylinder contains a piston 10, and the small cylinder contains two pistons 11 and 15. All three pistons are rigidly connected by al rod 14C so that they move in unison. lVhen the brakes are released, the pressure in the feed valve is. of course, substantially the same as that in the equalizing reservoir, hence at such time the three pistons 10, 15 and 11 are moved to the extreme right owing to the fact that the area of piston 10 is greater than that of piston 11, and because the chamber between pistons 1() and 15 is connected to atmosphere through a port 66. lllhen. a service application of the brakes is made, however, the pressure in the equalizing reservoir is reduced while that in the feed valve remains substantially the same as before. The relative areas of the pistons are such that when the pressure in the equalizing reservoir is reduced by an amount corresponding to the required brake application, the actual pressure on pistons 11 and 15 exceeds that on piston 10 so that the pistons then move to the left. Then the pistons are at the eXtreme right, as shown in the drawing, thepipe 6 is opened to cylinder 9 between pistons 11 and 15, but when the pistons move to the left piston 11 covers theiport by which pipe 6 enters the valve body and so disconnects this pipe from cylinder 9.

Reference character 16 designates a pipe the upper end of which leads into the upper end of a cylinder 17 which is integral with the casing of the valve device V. The upper end of the cylinder 17 also communicates with cylinder 9 by a port 20 which is so located that itA is always between pistons 1 1 and 15 regardless of the position of these parts. The connection between pipe 16 and port 2O is, however, controlled by a valve 18 in such manner that when this valve is in its uppermost position, as shown in the drawing. it disconnectspipe 16 from. port 20, but that when the valve moves downwardly pipo 16 is opened to port 20 and so to cylinder 9. The lower end of the cylinder 17 is connected with a pipe 21, which is normally closed but which may at times be opened to atmosphere b v means hereinafter explained. The valve 18 is provided with a port 182L of small area, so that normally the same pressure exists on both the upper and the lower sides of this valve. it such times the valve occupies its uppermost position owing to the action-of a spring If* however, pipe 21 is opened to atmosphere, the pressure on the upper sun face of the valve overbalances the pressure exerted by the spring 19 so that the valve moves downwardly and connects pipe 16' with port 20.

The lower end of pipe 16 is connected with a brake application valve device F which I will now describe. This valve device comprises a body 77 in which is a slide valve v78. The slide valve is controlled by a piston 7 3 which is rigidly connected with the valve and which operates in a cylinder 77a integral with the body of the valve. The valve body 77 is constantly connected with the main reservoir of the braking system through a pipe 81. l/Vhen the slide valve occupies its extreme right-hand position, as shown in the drawing, the main reservoir is connected with the feed valve of the braking system through a pipe 82, so that the brakes are then under the control of the operator of the vehicle; but when the slide valve is shifted to the left it covers the port leading to pipe 82 and so disconnects the feed valve from the main reservoir. whereby the operator cannot then release the brakes by manipulation of his brake valve handle. B. P. represents a pipe opening into the seat on which the slide valve operates, and which pipe leads to the brake pipe of the braking system. When the slide valve is in the position shown, it Covers the pipe B. P. so that no automatic application of the brakes can occur. When the slide valve moves to the left, however, a cavity 86 in the slide valve connects the pipe B. P. with an exhaust port 88 so that the pressure in the brake pipe is reduced and an automatic application of the brakes occurs.

The slide valve 78 and piston 7 9 are biased to the right by a spring 80, so that when the fluid pressures on the two sides of the piston are equal the slide valve occupies its right-hand position as shown. The pressures on the two sides of the piston are equal when the upper end of pipe 16 is closed for the following reason: Main reservoir pressure is constantly exerted on the rightehand side of the piston, and the piston is provided with a small port 79a through which the main reservoir pressure may flow to the lefthand side of the piston. The leftehand end of cylinder 77a is normally connected with pipe 16 through a pipe 90 and a cavity 85 in the slide valve. When, therefore. the upper end of pipe 16 is closed, the tluid pressures on the two sides of the pistons are equal so that the slide valve occupies its right-hand position owing to the influence of sprii'ig 80.

I will now assume that the upper end of pipe 16 is opened to atmosphere through pipe 6 and valve 4, as hereinbefore explained. This causes a reduction in pressure on the left-hand side of piston 79, so that the pressure on the right-hand side of this piston is then sufficient to move the piston and the slide valve 78 to the lef This movement of the slide valve opens pipe B. P. to atmosphere through the exhaust port 83 and so,

cause an automatic application of the brakes.

This movement of the slidevalve also diS- connects the feed valve pipe 82 from the main reservoir and so removes the control of the brakes from the operator of the car or train. This movement of the slide valve, furthermore, disconnects pipe 16 from pipe 90 and connects the latter pipe with a pipe 87, which is normally opened to atmosphere i through an exhaust port 88. The left-hand end of cylinder 77 is then connected with atmosphere through this exhaust port, so that the slide valve remains in its left-hand position until the exhaust of air from pipe 87 is discontinued. This exhaust may be discontinued by means of a push button valve, 89, which is located at such position on the vehicle as to require that the operator shall leave his cab and descend to the ground in order to operate` the valve. It follows, therefore, that once an automatic application of the brakes has occurred;` the vehicle must come to a full stop before the brakes can be released. That is, the construction of this valve device F is such that after it has been moved to brake applying position, the upper end of pipe 16 may be disconnected from atmosphere without affecting the position of the valve device, and the valve device can only be returned to its initial position by the operation 0f tlie push button 89. p

The operation of the apparatus thus far described is as follows:

As long as pipe 21 is closed, plunger 18 remains in uppermost position, so that pipe 16 is closed and no automatic application of the brakes occurs. When, however, pipe 21 is opened to atmosphere, valve 18 moves downwardlyT so that pipe 16 is connected with cylinder 9 of valve device V. Tf the pistons 10, 15 and 11 of this valve device are in the positions shown, iuid pressure can flow from pipe 16 into pipe 6, and if valve 4l is opened, the fluid can pass through this valve and out to atmosphere through port 7. Under such conditions, therefore, the pressure in pipe 16 is reduced so that an automatic application of the brakes is effected by valve device F. If, however, the brake valve handle .is at such time in the service or emergency position, valve 4 is closed so that the exhaust of air from pipe 16 is prevented at this point. Furthermore,if the equalizing reservoir pressure has already been reduced by such an amount as to cause the predetermined service application of the brakes, pistons 10, 15 and 11 will have been moved to the extreme left, thereby disconnecting pipe 6 from pipe 16. ln this event thereduction of pressure in pipe 16 will. be prevented by iston 11, so that an automatic application ofthe brakes does not occur. It will be seen, therefore, that the automatic application is prevented if the brake valve handle is in service or emergency position, or if an applcaton of the brakes is already in effect;

and it will furthermore be seenfthat if the predetermined service application is already in eect, the brake valve handle may be returned to the lap position and an automaticI by the slide valve, pipe 21 is closed so that.

valve 18 is in its uppermost position. That is, the air pressures on the two sides of this valve are equal and the valve is pushed upwardly by spring 19. `When, however, the slide valve 23 is moved upwardly, port 24 is uncovered, so that pipe 21 is opened to atmosphere, whereupon valve 18 moves downwardly owing to the reduction in the air pressure on its under side.

t will, of course, be observed that when port 211 is opened by slide valve 23, pipe 16 is connected with atmosphere through the port 18a. and pipe 21 even though piston 11 covers pipe 6 or valve 4- is closed. The area of port 18l is so small, however, that the rate of exhaust through this port is not suflicient to cause an automatic application of the brakes. i

Slide valve 23 is controlled by a speed responsive device, which, as here shown, is in the form of a centrifuge C. This centrifuge comprises a hollow shaft 25 journaled in a bearing` 26 and provided with diametrically disposed arms 25a, in which are pivotally mounted the bell cranks 27 of the centrifuge. Attached to the hollow shaft 25 is a spur gear 22 which is connected through suitable gearing (not shown) with a wheel or axle of the vehicle, so that while the vehicle is in motion the shaft 25 is constantly rotated at a speed proportional. to the speed of thev vehicle. The inner arnisof bell cranks 27 are provided with slots which coact with a pin 35 attached to a rod 28, which. rod passes through the hollow shaft 25 and is free to move longitudinally therein. The lower end of the rod 28 is connected withl slide valve 23, so that longitudinal movement of the rod 28 causes a corresponding` movement of the slide valve on its seat. The parts are so arranged and proportioned that when the bell cranks 27 of the centrifuge are in the closed position` the slide valve 23 covers the port 2411, but that when these levers fly outwardly, due to'centrifun'al action, the rod 28 is moved upwardly, so that the slide valve 23 uncovers the port 2/1 and thus opens pipe 21 to atinosphere.

Suitable means are provided for biasing the rod 28 downwardly, thus opposing the natural tendency of the centrifuge to open while the vehicle is in motion. As here shown. this biasing; means is arranged to exert. three different pressures on thev rod,

risas it lthus imposing three different speed limits on the vehicle. This biasing means comprises a cylinder 29 in which is a piston 30 attached to the upper end oit the rod 28. Also .located in the cylinder 2t) is a spring 32 one end ot which abuts against the piston 30 and the other end against a plunger 3l also movable within the cylinder. rhe spring 32 is so adjusted that when the plunger 3l is in its uppermost position, shown in the drawing, the pressure exerted on the rod 2e' through the piston 30 is of such value, that as long as the vehicle does not exceed a predetermined low speed, such as l5 miles per hour, the centrifuge will not open, but that it the vehicle exceeds this speed the centriiuge will overcome the action 'of the spring and so will move the slide valve 225 to uncover port 2d. This spring then, when expanded as shown, imposes on the vehicle what may be termed a low speed limit.

lilntering the cylinder 29 at the upper end is a pipe il which at times admits fluid pres-- sure to the 'upper surface ot' plunger 2li. lVhen this occurs, plunger 3l is driven downwardly until it engages with a fixed stop 38, thus compressing the spring and so increasing the pressure exerted by this spring against the head 30. The pressure opposing the action of the centrifuge is then such as to permit the vehicle to travel at a speed not to exceed a predetermined intermediate value7 such as 36 miles per hour, without opening` the centrifuge. The speed limit thus imposed may be termed the lntermediate speed limit.77

ln order to permit the vehicle to travel at high speed, such as 65 miles per hour, without opening the centrifuge, l provide a pipe which enters the cylinder 29 directly above the gisten 30. lvll/hen fluid pressure is supplied to this pipe 33, it causes a high pressure to be exerted directly on the piston 30, which pressure added to that of spring 32 permits the vehicle to travel at high speed (herein assumed to be 65 miles per hour) without causing the centrifuge to open. This pressure, then, imposes what may be termed the High speed limit.7

Fluid pressure, usually air, is at times supplied to the pipe 34 from a reservoir or other suitable source, this supply being con trolled 'by a valve 3G which in turn is controlled by an intermediate speed magnet M1. This magnet and valve are so arranged that when the magnet is cle-energized the valve disconnects the pipe 311 from the source ot pressure and connects this pipe with ati mosphere through an exhaust port 3T; but that when the magnet is energized the valve connects the pipe 3d with the source ot fluid pressure and closes the exhaust port.

The supply of fluid pressure to the pipe 33 is controlled in a similar manner by a valve 36EL and a high speed magnet MH.

The intermediate speed magnet M1 is controlled by an intermediate speed relay R1, the circuit being trom one 'terminal oi a source of current, through contact alla of relay lil, wire 39, magnet h and wire 40 to the other terminal t) ot the source orP current. The source oit current itself and the parts olE the circuit which do not pass in the parts ot the apparatus shown in the drawino are omitted for the salte oi: simplicity. lst will be seen that magnet Ml is energized or de-energired according as relay R1 is energized or not. The high speed magnet MH is similarly controlled by a contact il of a high speed relay RH, the circuit for this magnet being obvious from the drawing. The relays RH and lt are controlled by a polarized relay P in suoli manner that one relay or the other is energized according as armature contact l2 of the polarized relay l is swung in one direction or the other. The circuit for relay RH is from one terminal B of a source of current through contact @M49 of relay l, wires d3 and ed, relay RH and wire 45 to the other terminal O ot the source oi' current. The corresponding circuit for relay R1 is controlled by contact l -50 ot polarized relay l) and will be obvious 'from the drawing.

The circuits which have just been traced for relays lt and RI are in the nature ot pick-up circuits, and are merely for the pui poses oit preliminary energization of these relays. Tach relay is further provided with a holding circuit including a contact controlled by a shoe 5l which is arranged to coact with ramp rails A located in the trackway. rlhis shoe 5l. controls two contacts it and 52 which contacts are normally closed but are opened each time that shoe 5l is raised by a ramp rail A. The holding cir-- suit for relay RH is from one terminalld or a source ot' current, through contact a6, wire 47, contact i8 of relay RH, wire dll, winding ot relay RH, and wire 45 to the other lerminal O of the same source of current. The circuit ttor relaylI is controlled by contact 52 and by a contact 4 8 of the relay itself. and will be ob ious from the drawing without further explanation.

One terminal oi the polarized relay lD is connected with a wheel or aide ot the vehicle at the point indicateiil by the reiter-ence char acter (l, while the other terminal o'i this relay is connected with the shoe l by means ot a wire Means are provided in the tracltw as hereinafter explained, tor at times connecting suitable source of current with ramp rail and a traclr rail ot the railway. lt follows that when the shoe 5l jes with ramp rail il, relay P will be enc tvcized in one direction or the other according as the positive terminal of the lastmentioned source of current is connected with ramp rail A. or with the track rail; ob-

liti

viously, if this source of current is not connected with both the ramp rail and the track rail, relay Ij will remain deenergized. I will assume for purposes of discussion that when the positive terminal of the trackway source is connected with the ramp rail A, relay P is energized in such direction as to close contact 42-49 and so to energize the high speed relay RH. .This energization I will term the positive energization ot relay I3.

Referring now to Fig. 2, the reference characters T and T@- designate the track rails of a railway along which traliic normally moves in the direction indicated by the arrow. These rails are divided by suitable means, such as by insulated joints 65, into a plurality of successive block sections .l-K, K---L` etc. Located adjacent the entrance of each block is a signal which is designated by the reference character S with an eXponent corresponding to the location of the signal. The controlling means for these signals forms no part of my invention, and hence is omitted from the drawing 'for the sake of simplification. Each signal is adapted to indicate Stop when the corresponding block is occupied, Caution when the corresponding block is unoccupied and the block next in advance is occupied, and Proceed when the corresponding block and the block neXt in advance are both unoccupied; for example, as shown in Fig. 2, the block limmediately in advance of location L is occupied by a vehicle WV, so that signal SL indicates Stop, signal SK indicates Caution, and signal SJ indicates Proceed.

Loc-ated at or near the entrance end oi each block is a ramp rail A, and located at a suitable distance in the rear ot each ramp rail A is a second ramp rail A. Each ot' these ramp rails is arranged to coact with the vehicle-carried shoe 51, shown in Fig. l, in such manner that the shoe is elevated to open. contacts 46 and 52 each time that the shoe passes. over one of these rails. Current is at times supplied to each ramp rail A. by an adjacent source oft' current E, and, similarly, current is at times supplied to each ramp rail A by an adjacent source E. Consiilering first ramp A, the supply of current therefor is. controlled by contacts and 55 operated by the adjacent signal S. the control being` such that when the signal indicates proceed, the positive terminal ofthe source E is connected with the ramp rail A and the negative. terminal with the lower track rail T; but that when the signal indicates caution. the polarity is reif'ersed` so that'the negative terminal oi" the source E is connected with ramp rail A and the positive terminal with the track rail rIl. When the signal indicates stop, the source` E is disconnected from ramp rail A so that this rail is then dead. When the signal is in the proceed position (see signal SJ) the positive terminal of battery E is connected with ramp rail A through contact 55 and wire 57, and the negative terminal is connected with the track rail T through contact 54 and wires 59 and 58. lVhen, however, the signal indicates caution (see signal SK), the positive terminal of battery E lis connected with rail T, through wire 6l, contact 54 and wires 59 and 58; Whereas the negative terin in al is connected with ramp rail A,through wire 60, contact 55 and wire 57.

The connection between each battery E and the corresponding` ramp rail A is co-ntrolled by acontact 56 operated by the adjacent signal, the control being such that the positive terminal ol the battery is connected with the ramp A when the adjacent signal indicates proceed or caution, but that the connection is broken when the signal indicates stop.

The operation ot` the entire appara-tus is as follows:

Referring l{irst to Fig. 2, I will assume that while the vehicle W is in the position shown on the drawing, a second vehicle equipped with the apparatus shown in Fig. l, approaches block J-K. As this second vehicle passes over ramp rail A in the rear of location J, the shoe 5l will be elevated to open the holding circuit of whichever relay RH or RI was previously energized, but at the same time polarized relay will be energized in such direction as to close the pick-up circuit for the high speed relay XH, because the positive terminal of the adjacent source E is connected with this ramp rail. rIhen as the shoe 51 passes oil of rail A', the holding circuit for this relay RH will be closed at contact 46. High speed magnet MH is then energized so that the. vehicle can proceed at 65 miles per hour or less. Ramp rail. A at location .l is connected with the positive terminal of its battery E, so that the saine operation takes place as the vehicle passes' over this ramp rail. The vehicle may then proceed into block J-K at full speed.,

Bail A immediately in the rear ot location I( is connected with the. positive terminal of its battery E', so that the same operation again takes placeas the vehicle passes over this ramp rail. Itamp rail A at location K is, however, connected with the negative terminal of its battery lil, so that as the vehicle passes over this ramp rail polarized. relay IJ will be energized in such direction as to close the pick-up circuit tor the intermediate speed relay RI. The high speed relay RH, of course, becomes cle-energized, because its holding circuit is opened at contact 46. The opening of relay RH causes the high speed magnet MH to become de-energizefd, so that the supply of fluid pressure to pipe is discontinued and this pipe is opened lli to atmosphere. The intermediate speed magnet M1 becomes energized, however, so that fluid pressure is supplied to the cylinder 29 above the plunger 31. Assuming that the vehicle is t-raveling at the high speed limit, that is, (35 miles per hour at this point, it, of course, follovvs that centrifuge C Will open, so that slide valve 23 will be elevated to uncover port 24. If the engineer' or operator of the vehicle recognizes the indica tion given by signal SK and moves his brake valve handle to service posit-ion just before this ramp rail A is reached, the pipe 6 will not be connected to atmosphere and so an automatic application of the brakes will be prevented. Likewise after the service application of the brakes has been effected the pistons 10, 15 and 11 of the valve device V Will move to the left, so that the operator may return his brake valve handle to the lap position and the automatic brake application Will still be prevented. The speed of the vehicle will then be gradually reduced, as indicated by the curve 74. Tvllhen the speed is reduced to slightly under 35 miles per hour the centrifuge will close, so that the operator may release the brakes by the proper manipulation of his brake valve handle and then proceed at a constant speed., as indicated by line 75, until ramp rail A is reached. That is, the operator may re* lease the brakes at the point 71 in Fig. Q or shortly thereafter. Ramp rail A in the rear of location L is disconnected from its source of current, so that as the shoe 51 passes over this ramp rail the intermediate speed relay RI will become de-energized. This causes de-energization of the intermediate speed magnet MI, so that the supply of air to the upper end of cylinder 29 is discontinued. 1f the vehicle is still travelingl at 35 miles per hour or slightly less, the centrifuge C Wiill again open, whereupon port 2st yvill again become opened and valve 18 will move downwardly to connect pipe 16 with the interior of valve device V. If, just prior to rea-ching this ramp rail A', the operator again moves his brake valve handle to the service position, an automatic application of the brakes will again be prevented and the brake valve handle can be returned the lap position after the service application has become effective. The brakes nonT being applied, the speed of the vehicle Will be reduced, as indicated by the curve 76 in Fig. 2. lVhen the point 73 is reached, that is, when the speed of the vehicle is reduced to 15 miles per hour, centrifuge C Will close so that the brakes may then be released and the vehicle may then proceed at this loiv speed limit into the block occupied by the vehicle W.

' tion of the apparatus I have assumed that the operator of the vehicle controls the vehicle manually in accordance with the indications given by the signals SK and SL. I will now assume that the vehicle approaches signal SK at miles per hour, but that the operator does not observe the yindication given by this signal, that is, that he does not move his brake valve handle to cause an ap plication of the brakes. Then as the vehicle passes over the ramp rail A adjacent this signal, the valve 18 will move downwardly so that pipe 16 will be connected with atmosphere through pipe 6 and valve el. This will cause operation of valve devfce F to effect an automatic application of the brakes. Vhen the speed has been reduced to a little less than 35 miles per hour, the centrifuge Will close so that valve 18 will return to its initial position, but this does not affect valve device F. The brake application Will continue, therefore, until the vehicle is brought to a full stop, a considerable distance in the rear of signal SL. Again, let it be assumed that the operator applies the brakes at the point by the proper n'ianipulation of the brake valve handle and again releases the bri kes at point 71, so that the vehicle proceeds at 35 miles per hour or less, -as indicated by the line 7 Then let it be assumed that at ramp rail A, that is at point 72, the operator fails to acknowledge the stop indication of signal SK by a further manipulation of the brake valve handle. Valve 18 Will again move downwardly, so that pipe 16 will then be opened to atmosphere through pipe 6 and valve et, thus causing an automatic application of the brakes which Will bring the vehicle to a stop in the rear of signal SL.

It will be noted that in the event that an automatic application occurs, the brakes cannot be released until the vehicle is brought to a full stop, because the release button 89 can be reached only from the ground. This full stop serves a penalty to the operator for non-observance of the signal indications.

Although I have herein shovvn and described only one form of apparatus embodying my invention, it is understood that varions changes and modifications may be made therein Within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention` what l claim is:

1. ln combination, a railway vehicle provided with a braking system, automatic apparatus for causing an automatic application of the brakes vvhen said vehicle exceeds certain prescribed limit speeds during its progress along the track, and means for preventing operation of said automatic apparatus said means beingl effective only when the brakes have been applied manually by the operator of the vehicle.

2. ln combination, a railway vehicle provided with a braking system, automatic apparatus for causing-an automa-tic application of the brakes when said vehicle exceeds certain prescribed limit speeds during its progress along the track, governing means under the control of the operator for governing` the speed of the vehicle, and means dependent upon the operation of said governing means to a degree sufficient to cause retardation of the vehicle vfor preventing operation of said automatic apparatus.

3. In combination, a railway vehicle provided with a braking system includinga manually operable control device for causing a brake application, automatic apparatus for causing automatic application of the brakes when said vehicle exceeds'certain prescribed limit speeds during its progress along the track, and means responsive only to an actual application of the brakes by operation of said control device for preventing' operation of said automatic apparatus.

4;. In combination, a railway vehicle provided with a braking system including a manually operable control device for causing a brake application, automatic apparatus for causing automatic application of the brakes when said vehicle exceeds cert-ain prescribed limit speeds during its progress along the track, and means dependent upon a brake application of predetermined value by the action of said manually operable control device for preventing operation of said automatic apparatus.

5. In combination, a railway vehicle provided with a braking system including an equalizing reservoir and a. feed valve pipe, automatic apparatus for causing a brake application in the event of one ratio of pressures existing in said equalizing reservoir and feed valve pipe when the vehicle exceeds certain prescribed limit speeds during its progress along the track, and means dependcnt upon a different ratio of pressures in said equalizing reservoir and said feed valve pipe for preventing operation of said automatic apparatus.

6. In combination, a railway vehicle provided with a braking system, automatic apparatus for causing an automatic application of the brakes when said vehicle exceeds certain prescribed limit speeds during its progress along` the track, and manually operable means for preventing such automatic application provided the brakes have been .applied-by the operator of the vehicle, said manually operable means being ineiiiective to release the brakes after they have been applied by said automatic apparatus.

7. In combination, a railway vehicle provided with a braking system, automatic apparatus for causing an automatic applicationof the brakes upon a prescribed change in traffic conditions if the speed ofthe vehicle exceeds a prescribed value, and manually operable means for preventing such automatic application of the brakes, said means being effective only when the brakes have been applied manually by the operator of' the vehicle.

, 8. In combination, a railway vehicle provided with a brak-ing system including a manually operable brake control device, automatic means for causing an application of the brakes, and means for preventing operation of said automatic means which said brake -control device is in brake-applying position and for `continuing to prevent operation of said automatic means after said device is subsequently restored away from brake-'applying position if and while a brake application of predetermined value is in effect vdue to operation of said device.

9. ln combination, a railway vehicleprovided with a braking system, automatic means for causing application of the brakes, and means dependent upon a. brake application. oia at least a predetermined value for neventing operation of said automatic means.

l0. In combination, a railway vehicle provided with a .braking system includinga manually operable device for causing' application of the brakes, automatic apparatus for also causing application of the 'brakes under certain traflic conditions, and means for preventing` operation of said yautomatic apparatus while said device is in position to initiate a brake application and also after said device has been restored away from initiating position if and while a brake application oi at least predetermined value is in effect due to said device having been in initiating position.

1l. In combination, a railway vehicle provided with, a braking system, a centrifugal device on the vehicle, means for opposing the opening of said centrifugal device by av variable force whereby if the actual speed of the vehicle at any instant exceeds the permissive speed corresponding to the force then opposing the centrifugal device the .said device will open, automatic means controlled by said centrifugal device for causing a brake application when said device opens, and means for preventing operation of said automatic means if the brakes have been applied by the operator of' the vehicle.

12. ln combination, a railway vehicle provided with a braking system, means on the` vehicle for establishing several permissive speeds, speed responsive means on the ve-` hicle, automatic apparatus controlled jointly by said two means for causing an application; of the brakes if the act-ual speed eX- ceeds the permissive speed Iat any given instant, and means for preventing operation of said automatic apparatus, said means being,` efecti ve only when the brakes have been applied by the operator otl the vehicle to cause retardation of the vehicle.

13. Railway trafiic controlling` apparatus con'iprising a plurality ot' block sections, :i ramp rail A tor each section located adjacent the entrance end ot the section, a second ramp rail A for each section located in the rear oit the entrance end ojt the section 5 means 'for each rail A for energizing' the rail with current oll positive polarity when the c respondingl section and the section next in advance are unoccupied, tor energizing' the rail with current ot negative polarity when the coiaespoi'iding section is unocciuiiicd and the section next in advance is occupied, and for gleenergizing the rail when the corrospondinc section is occupied; means tor each rail A 'for energizing` the rail with current ot positive `iolarity when the corresponding section is unoccupied and tor de-enerrizinf;` the rail when the correspointing` section is occupied; automatic apparatus'on a vehicle controlled by said ramp rails for causing an automatic brake application it the vehicle exceeds a predetermined high speed limit a'l'ter passing a positively energized rail, it the vehicle exceeds a predetermined intermediate speed limit after passing' a negatively energized rail, and it the vehicle efr.- ceeds a predeterniined low speed limit atter passing a cle-energized rail; and means acting to prevent operation ot said automatic apparatus it the operator ol the vehicle applies the brakes manually when passinga` a negatively energized rail and a cle-enen gized rail.

11i. Railway tral'lic controlling` apparatus comprising a plurality7 ol block sections, a ramp rail A for each section located adj acent the entrance end of the section, a second ramp rail A for each section located in the rear of the entrance end of the sec-tion; means for each rail A for energizing the rail with current of positive polarity when the corresponding section and the section next in advance are unoccupied, tor energizingr the rail with current ot negative polarity when the corresponding' section is unoccupied and the section next in advance is occupied, and tor cle-energizing the rail when the correspondingl section is occupied; means for each rail A for energizing the rail with current of positive polarity when the corresponding section is unoccupied and for cle-energizing the rail when the corresponding section is occupied; automatic. apparatus on a vehicle controlled by said ramp rails 'for causing an automatic brake application if the vehicle exceeds a predeten mined intermediate speed limit atte-r passing a negatively energized rail, it the vehicle exceeds a predetermined low speed limit after passing a cle-energized rail, and for permitting` movement ot' the vehicle at high speed without causing` an automatic brake application after passing' a positively ener- `ijized rail; and means acting to prevent operation of said automatic apparatus it the operator ot the vehiclev applies the brakes manually when passing a negatively energized rail and a cle-energized rail.

15. Railway tratiic controlling apparatus comprising a plurality of block sections, a vehicle; apparatus on the vehicle adapted when in one condition to cause an automatic application ot the brakes if the speed eX- ceeds a predetermined intermediate value, and when in another condition to cause an automatic application otl the brakes it the speeds exceeds a predetermined lower value: means located adjacent the entrance end of each section tor placing said. apparatus in the Erst-mentioned condition when the section next in advance is occupied, means located in the rear of the entrance end ot each section for placingl said apparatus in the second mentioned condition when such section is occupied, and means on the vehicle acting to prevent operation ot said appa-A ratus it the brakes are applied through the usual manually operable means.

16. Railway traliic controlling apparatus comprising a plurality of block sections, a vehicle; al'iparatus on the vehicle adapted when in one condition to cause an automatic application ot the brakes if the speed exceeds a predetermined intermediate value, and when in another condition to cause an automatic application of the brakes if the speed exceeds a predetermined lower value; means tor placing said apparatus in the first-menitioned condition when `the vehicle enters the section in the rear ot an occupied section, means for placing said apparatus in the second mentioned condition when the vehicle reaches a point at a predetermined distance in the rear of an occupied section, and means on the vehicle acting to prevent operation of said apparatus it the brakes are applied through the usual manually operable means.

17. In combination, a railway vehicle provided with a braking system, apparat-us for causing an automatic application oit the brakes and for preventing releaseof the brakes at'ter such application has occured until the vehicle has been brought to a full stop, and means acting when the brakes have been applied manually by the operator of the vehicle :tor preventing action ot said apparatus.

18. In combination, a railway vehicle provided with a braking system, a valve device for causing an automatic application of the brakes and arranged to remain in brake applying position after once being placed there until the vehicle has been brought to a full stop, apparatus for placing said valve device in brake-applyinpr position when the vehicle exceeds certain prescribed limit speeds during its progress along the track, and means acting when the brakes have been applied manually by the operator of the vehicle for preventing actuation ot' said valve device to brake applying position.

19. In combination, a railway vehicle provided with avbraking system including a manually operable brake valve, automatic means forv stopping the vehicle if certain prescribed limit speeds are exceeded by said vehiclein its progress along the track, and means controlled by said manually operable valve and eective only the valve is held in brake applying position long enough to actually apply the brakes, for preventing said action of said automatic means.

20. In combination, a railway vehicle provided ivith a braking system including a manually operable device :tor causing a brake application, automatic apparatus for also causing an application of the brakes, and `means dependent upon the operation ot said manually operable device for a period of time suilicient to cause retardation of the vehicle for preventing` operation said automatic apparatus. v y

21. In combination, a railway vehicle provided with a braking system, automa-tic apparatus for causing a brake application, and means ,dependent upon the manual application ot the brakes to ya. sul'licient degree to.

cause retardation of the vehicle for preventing operation of said automatic apparatus.

22. ln combination, a railway vehicle provided With ar braking system including` a manually operable device 'for causing a brake application, automatic apparatus if'or also causing an application of the brakes,

, and means dependent upon a brake application of predetermined value bythe action of said manually operable device for preventing operation of said automatic apparatus. i 23. In combination, a railway vehicle provided with a brakingvsystem including a manually loperable device for *causing a brake application, automatic apparatus for also causing` an application oi` the brakes, and means effective only when the brakes are actually applied through the medium ot said manually operable device 'for preventing operation of said vautomatic apparatus.

24. Railway ltratlic controlling apparatus comprising means on a train controlled from the trackivay `for imposing a continuously effective speed limit. under one given condition oftraflic in advance of the train, means for automatically applying the brakes of the train'iij such speed limit is exceeded,

and apparatus underv the control of the engineer effective it operated previous to the Ainitiation of such automatic brake applica-V tion toprevent an automatic application when such speed limit is exceeded.

25. Railway trailic cont-rolling apparatus comprising apparatus on a train controlled from the trackway for automatically applyingi` the brakes it the train exceeds certain continuously effective fixed speed limits determined by tratlic conditions in advance, and manually operable means effective to prevent such automatic brake application but ine'l'l'ective to release the brakes after they have been applied by said automatic apparatus.

26. The method ot' controlling railway traiiic which consists in establishing a continuously effective speed limit on a train determined by tra-Hic conditions in advance of the. train, applying the brakes automatically if the established speed limit is exceeded at any moment, and preventing such automatic application it the engineer takes suitable action prior to exceeding the established speed limit.

27. The method of controlling yrailway traffic which consists in establishing a continuously effec-tive speed limit on a train de* termined by traine-conditions in advance of the train, applying the brakes automatically if the established speed limit isexceeded at any moment, and preventing such automatic application it the engineer applies the brakes manually prior to exceedingl the established speed limit and keeps themapplied as long as the speed limit is exceeded.

28,. In combination, a railwayv vehicle` provided` with a braking system, automatic apparatus on the vehicle for causing'an automatic application of the brakes, and means tor preventing operationjof said paratus if and only if the brakes are actually applied by a manual action the kpart of the driver oi the vehicle. l

29. In combination, a railway vehicle, automatic apparatus thereon for causing re tardation oi the vehicle, and means for. preventing operation of said apparatus if only it the driver performs an Aact which will actually retard the vehicle. y

In testimony whereof` I aillx my signature in presence oftwo Witnesses. i

l? RANK NICHOLSQN, Witnesses A. HERMAN WueNnR, E. P. CHUM. 

